Rotary oil burners



Sept. 11, 1962 J. J. MCGILLIS ET AL ROTARY. OIL BURNERS 3 SheetsSheet 1 Filed Nov. 16, 1959 l 4 I II l ll Sept. 11, 1962 J. J. M GILLIS ET AI. 3,053,314

ROTARY OIL BURNERS Filed Nov. 16, 1959 3 Sheets-Sheet 2 Joiaia JMcM'ZZIJs,

P 1962 J. J. MOGILLIS ET AL 3,053,314

ROTARY OIL BURNERS Filed Nov. 16, 1959 3 Sheets-Sheet 5 HugoazD.M0 GiZZIJs,

*7" 1 mm Lam by Wfim, 1 Jifiym for complete and rapid combustion.

United States Patent 3,653,314 ROTARY 01L BURNERS John J. McGillis, 339 Ash St., and Hugh D. MeGillis, 78 Manomet St., both of Brockton, Mass. Filed Nov. 16, 1959, Ser. No. 853,326 5 Claims. (Cl. 158-77) This invention relates to rotary oil burners, and more particularly to rotary oil burner heads such a disclosed in our prior Patents Nos. 2,738,837; 2,815,806; 2,836,231 and 2,893,480, and wherein liquid oil fuel is atomized and distributed for mixing and burning with air outside the head.

Rotary oil burner heads of the type here concerned are characterized more particularly by a pair of opposed dished distributing plates or discs spaced apart on a hollow shaft through which oil is delivered to the space or chamber defined between the said plates or discs. The oil is forced out of multiple radial shaft openings in fine streams which are broken up or atomized by engagement with obstructions within the chamber. Thence the oil is carried to the periphery of the burner head where it is ignited with air supplied to aid combustion.

Heretofore, it has been the practice to convert the oil to spray form by atomizing it in a chamber from which air is excluded, and by then discharging the oil, by the action of centrifugal force and oil pressure, from about the circumference of the chamber, the same constituting the aforesaid periphery of the burner head. Air is excluded from the interior of the chamber because it has only the peripheral opening between the burner head plates through which the oil flows radially outward. Cooling air passes through the burner head, but in conduits which are open only to the exterior of the chamber, and carry air from outside the lower to pass. over the upper of the two distributing plates. The atomizing of the oil in the absence of air and the cooling of the burner head will be understood to combine to reduce the incidence of flash back and burning within the head.

But the described mode of discharging the atomized oil directly from the atomizing chamber is also found not to divide or break up the oil as finely or fully as necessary Relatively large globules are observed to be discharged from the burner head, and the greater portion of the oil to be thrown outward through the space between the distributing plates, without benefit of atomizing contact with their sharp edges.

Thus the operation of the rotary oil burners here concerned has suffered from smokiness and the accumulation of carbon deposits on the burner head parts. The prior burners have also been found to give trouble under high back draft and other adverse operating conditions. The incomplete combustion thus evidenced has of course resulted in the costly wastage of fuel oil. And the economies to be realized from the use of the low cost, heavy grade fuels have been denied to the conventional burners.

The present invention improves on the prior apparatus by achieving a significantly higher degree of atomization of the fuel oil, resulting in a marked decrease in the mentioned carbon deposits, and more generally in improved combustion efficiency even under adverse operating conditions and as. reflected by appreciably reduced fuel consumption.

A more complete atomization of the fuel oil is obtained under the invention by first breaking up the oil in a substantially air-free atomizing chamber, and then directing the undiluted oil onto a rotating heated surface. In this, multiple oil streams are directed radially at an intersecting annular distributing surface, the streams issuing at high velocity under supply pressure and as impelled also I lCC by centrifugal force. The oil streams are finely divided by battle and screen in the atomizing chamber en route to the distributing surface. But when the very fine high velocity undiluted oil particles strike the very hot high speed distributing surface they merge or coalesce there as an extremely thin film.

Further in accordance with the invention, as the oil film is spread outwardly by the rotation of the distributing surface it is subjected to a controlled air blast, which air blast drives the oil to and off the knife edge of the distributing surface, and in so doing still further thins and accelerates the film. This controlled airblast is defined more particularly as an annular, high velocity stream tangentially directed and at a substantial angle to the distributing surface so as to spread and thin but not to combine with the oil film, while accelerating its flow to the knife edge.

This described non-diluting atomizing of the oil, then reuniting the particles as a very fine film on a hot,.-rotating spreading surface, and then still further thinning and accelerating that film with a powerful annular air blast, will be understood to permit the utilization of oil of a more viscous or heavier grade than has heretofore been suitable for use with the concerned rotary burners, and so to yield higher heat output while at the same time lowering fuel cost and consumption.

Further, in accordance with the invention, after the extremely thin oil film has been driven as described to the periphery of the spreading surface, it is discharged only from the knife edge of that surface. In this, the thinness of the film enables practically all of the oil particles to be thrown directly from the knife edge and not be merely flowed around it. After leaving the discharge edge, the finely atomized oil is intersected by an annular hot air stream of a force and volume to very finely divide and intimately admix with the oil particles. This reducing of the. very finely atomized oil to a still finer spray by a powerful, enveloping, hot air blast will be understood to produce a completely clean burning fuel-air mixture in an annular region surrounding the head.

It is further to be noted that the powerfully and outwardlydirected oil and air streams hereof impart to the invention burner not only a finer atomization and better burning but also a self cleansing action, the same preventing the accumulation or deposits of carbon or the like impurities, and so increasing the operating life and efiiciency of the rotary oil burner here concerned.

In the accompanying drawings:

FIGURE 1 is an exploded perspective view with parts broken away to show the underlying construction of a rotary oil burner embodying features of our invention.

FIGURE 2 is a medial cross section of our burner at approximately double the scale of FIGURE 1, with parts of the shaft shown in elevation.

FIGURE 3 is a bottom plan view of the burner head with the bottom cap partially broken away to show the enclosed fan.

FIGURE 4 is a fragmentary horizontal section on line 44 of FIGURE 2.

v FIGURE 5 is a top plan view of the burner head with the cover plate partially broken away to show the wiper element.

Referring to the drawings, our improved rotary oil burner head is supported as conventionally on a vertical shaft 34 mounted for rotation by a high speed motor 29 and of the usual hollow structure for passage upwardly therein of oil from a suitable supply, not shown. For securing thereto the elements of the burner head, shaft 34 has a cylindrical enlargement 42 and two threaded portions 44, 46 of a smaller diameter at opposite sides of the said enlargement.

Two dished distributing plates 48, 50 are received at central openings therein on the threaded shaft portions 44, 46 respectively, and the plates are rigidly held by clamping-nuts 52, 54 for rotation with the shaft and at a spacing determined by enlargement 42. The transverse plates are seen also as arranged with their inclined peripheral or dished portions projecting oppositely inward, one toward the other, and extending from the spacing of the parallel plate portions such that the plates define therebetween a substantially enclosed space or atomizing chamber 55.

Mounted within the chamber 55 is an annular array of tubes 60 supported between plates 48, 50 and defining a series of vertical passages traversing the atomizing chamber and opening at both sides thereof through apertures 62 in said plates 48, 50. The tubes 60 are conveniently clamped by punching or stamping the plates 48, 50 at their openings 62 and to form the locking collars 63 which are seen to engage within the tube ends.

The tubes 60 are thus arranged to conduct air from below plate 48 to above plate 50 while effectively sealing at their ends against any escape of air into the atomizing chamber 55, whereby the said chamber remains substantially air-free as hereinbefore mentioned. The same tubes 60 define also and at their outside walls a series of intervening annular barriers or obstructions of the atomizing chamber 55, the same having deflecting surfaces arranged and functioning as hereinafter more particularly described.

The main fuel oil supply passage in hollow shaft 34 is seen to extend into and terminate upwardly, as at 43, within the enlargement 42, through which a communicating series of small bores or passages 64 extend radially outward. A series of annular oil deflecting elements or discs 49 are spaced around the circumference of the said enlargement 42, and more particularly are loosely received on the stems of and held behind the heads of screws 51 threaded part way into alternate ones of the passages 64.

As best seen from FIG. 4, the deflecting elements are proportioned to overlie the open passages 64 sufficiently to intersect and break up the oil streams issuing therefrom.

At least the oil passing between and some also of that deflected by the discs 49 next engages, in its radially outward travel, against the tubes 60 earlier described. The oil thus undergoes a further deflection and atomizing by the intermediate annular obstructions 60.

Outwardly of and surrounding the pipes 60 there may be provided an annular grid or screen 53 spanning and held between the plates 48, 50. The screen 53 will be understood to be of a gauge or mesh such as still further blocks and breaks up the oil particles as they are forced therethrough.

According to the invention lower plate 48 has an inclined or dished peripheral portion or annulus 4811 extending, say, half way toward the base of upper plate 50, whereas the said upper plate has a dished peripheral annulus 50a extending, say, twice as far, or approximately to a horizontal line with the base of lower plate 48. The plate portions 48a, 5021 are shown as inclined at approximately the same angle and such that a slight clearance or spacing is provided between the outer edge of plate 48 and the inside face of annulus 50a where it overhangs the same. The outer edges of annuli 48a and 50a will be understood to be tapered or pointed to present very sharp or knife edged peripheries.

It is readily seen that the quantity of outwardly flowing oil is affected by the width of the aforementioned spacing between the edge of plate 48 and the inside face of annulus 50a, and that the spacing is determined by the angles of incline of the annuli, the relative diameters of plates 48 and 50, and the width of enlargement 42. Thus, reducing the width of enlargement 42 will result in a smaller spacing, as will increasing the angle of incline of annulus 5011 or the diameter of plate 48. This plate 48 edge to annulus 50 face spacing must be wide enough to prevent the backing up of oil within the atomizing chamber yet small enough to insure that all of the outwardly flowing oil is deposited on the spreading or distributing annulus.

The angles of incline of the annuli will also be seen to affect the degree to which the burner head atomizes the oil. The angle of incline must be small enough to allow radially outward flow of the oil film, yet large enough to insure that the oil will be discharged from edge 57 at an angle which insures maximum atomization. Further, the angle which the annulus 50a makes with the radial direction must be that which insures that the oil is on the distributing annulus a length of time suflicient for the desired influence by the annular air blast.

In practice, it has been found that the best results in terms of thinness of film forming and finest edge atomizing are obtained when the inclined annuli define an angle between them in the range of 75 to degrees and when the aforementioned spacing is in the range of to /2 inch.

Further, means are provided for delivering an annular tangential air blast against the underside of annulus 50a and comprising in the illustrated embodiment a fan 66 adjacent the underside of annulus 48a. The fan may be formed from a disc having its peripheral annulus radially cut and twisted to present a plurality of blades which lie close to and are inclined as the outer surface of annulus 48a. The fan 66 thus produces a powerful annular air blast at a point close to and which bears upwardly-outwardly against the oil traveling down annulus 50a. The fan disc 66 also has openings 62 corresponding to the openings in plates 48, 50 to allow passage of air from the area below the burner head into tubes 60.

Means are provided also for forcing cool air upward, from below the burner head, herein comprising cap fan 71 which is secured to shaft 34 by collar 35. Cap fan 71 in addition to drawing air from below for delivery through tubes 60, provides a smooth, contoured surface insuring smooth air flow from below the head to blades 66 with minimum turbulence. An additional internal fan 65 may be added on shaft 38 between fan 71 and lower plate 48 to increase the air flow through the head. The air delivered by fans 65, 71 is propelled through openings 62 in plate 48 and thence to openings 62 in plate 50.

Means for confining the air delivering through the openings 62 in plate 50 to a region adjacent the top surface of plate 50 and obtaining an air stream undiluted by oil in the vicinity of edge 57 is provided by a third dished plate 56 spaced above plate 50 and clamped between the nut 54 and spacing collar 58 when plate 50 is clamped against the enlargement 42 during assembly of the head. Plate 56 in the illustrated embodiment is a duplicate of plate 50 and consequently its edge is at the same radial distance as and adjacent to edge 57.

A wiping means may be provided for further insuring that during operation the knife edge 57 is free from residue accumulated during non-use of the heater. In the illustrated embodiment a resilient wiper indicated generally at 59 is located in the space between plates 50 and 56 and has an annular central portion 47 for loosely fitting around collar 58 and two arms 61 which extend radially outward and are bent to conform to the outer surface of plate 50. Further, the ends of arms 61 are bent to engage over edge 57. Thus, when the burner head starts to rotate, wiper 59 remains stationary due to inertia whereby the ends of arms 61 scrape the edge 57 of plate 50 ridding it of carbon deposits and sludge accumulated during non-use of the heater. As the burner head gets up to speed, the friction between wiper 59 and upper plate 50 causes the wiper to rotate with the burner head. As the wiper spins, centrifugal force tends to straighten the bends in arms 61 whereby the arms pull away from the edge 57 so as not to interfere with the discharge of oil from edge 57 during ordinary operation of the burner head.

During operation, as the burner head starts to rotate cool air is drawn from below by fans 65, 71 and is propelled through tubes 60 in atomizing chamber 55 thereby cooling the burner head while at the same time becoming heated so that it discharges as an annular stream of hot air around the knife edge 57 of plate 50.

Oil conducted through shaft 34 delivers through radial passages 64 into the atomizing chamber 55. The oil is forced centrifugally outward between plates 48, 50 and is diffused and heated by deflecting elements 49 and tubes 60. Thence the oil passes through hot annular grid 53 which further reduces the droplet size of the atomized oil. The oil which has been atomized by repeated and continual deflections within the atomizing chamber in the absence of air flows outwardly to and is focused on a portion of the inner spreading or distributing surface of inclined annulus 50a of plate 50.

As previously mentioned the said inclined annulus Stia inclines towards but is spaced slightly apart from the edge of plate 48, and in substantial part surrounds or overlaps its annulus 48a. Thus oil which is delivered to the discharge edge of the burner is a reformed oil film unmixed by any air from the atomizing chamber and which has been driven down the inside face of inclined annulus 50a.

As soon as the oil is driven outwardly by centrifugal force past the edge of lower plate 48, it is subjected to an annular tangentially flowing blast of air from fan 66 which further thins and accelerates the flow of the undiluted, finely atomized hot oil film. The air blast may achieve its further thinning action by accelerating the surface layers more than the under layers of the oil film thus tending to spread the film in its travel across the distributing surface to the discharge edge 57. In any case the air blast from fan 66 is considered to squash but not also to mix with the extremely thin oil film while it remains on annulus 50a. It will be understood that the surface of annulus 50a not only functions conventionally to distribute the outwardly flowing oil about the circumference of a circle, but also functions as a spreading surface for cooperating with the annular air blast from fan 66 to accelerate and squash the outwardly flowing oil film.

The extremely thin hot oil film, driven outwardly by centrifugal force and by the fan 66, is forced at high speed off the knife edge 57 of plate 50 from which it is discharged in a finely atomized condition and subject for the first time to the action of air for mixing. It will be understood that a thin oil film unmixed with air discharges from edge 57. The oil treatment hereof, characterized as just mentioned by the reforming of a thin film unmixed with air, is thus distinguished also by discharge of practically all of the oil over the knife edge, or in other words by substantially complete knife edge atomizing.

Further according to the invention, a controlled air supply is combined in combustible mixture with the oil outside the burner head, and there comprises the annular air blast supplied through tubes 60 and forced downwardly between the parallel dished portions of plates 50, 56 to intersect the oil as it is thrown off, in a generally radial direction, from the knife edge 57.

Any suitable means may be provided adjacent the burner head for igniting the flammable mixture provided by the intersection of the discharged atomized oil and the hot air blast in the annular region around the burner head.

Mixing air may be supplied from the region below the head for intersecting with the aforementioned air blast.

Actual operating experience with the invention burner has demonstrated that its construction and operation as above described produces a substantially thinner film of undiluted oil and which is more finely atomized than heretofore. Further, the close arrangement of the power intersecting air blast has been found to provide a regulated air supply yielding a more efficient or complete combustion, and producing a hotter flame with less unreduced carbon.

Further, we have found that more viscous oils may be used in our burner head than has been possible with prior burners, and that the utilization of these heavier oils results in reduced fuel flow requirements for a given heat output as compared with conventional burner heads even under adverse high back draft conditions.

We claim:

1. A rotary oil burner comprising: rotary drive means; lateral top and bottom dished plates mounted concave toward each other and coaxially in spaced relation on said drive means and together defining an atomizing chamber; said dished top plate including an annulus extending exteriorly of said chamber beyond the edge of and to overhang substantially the entire dished portion of said bottom plate, said annulus defining a wide annular fuel spreading surface; air conduits traversing said chamber and connecting the region below said bottom plate with the region above said top plate; a first fan means mounted on said drive means below said bottom plate for driving air vertically upward through said conduits thereby cooling said atomizing chamber without the introduction of air thereinto; means for feeding fuel to said atomizing chamber, said fuel upon actuation of said rotary drive means being thrown radially outward and focused by the converging dished portions of said plates and reformed outside of said atomizing chamber as a thin film flowing unmixed with air from inner to outer edge portions of said fuel spreading surface; and a second fan means mounted for rotation with said bottom plate and positioned between said bottom plate and said overhanging spreading surface, said second fan means generating at points close to said spreading surface a powerful rotating annular air blast, said second fan means also being inclined to direct said air blast upwardly-outwardly against the oil film flowing across said spreading surface, said air blast further thinning by squashing and angularly accelerating said oil film whereby it is discharged at high speed from the peripheral edge of said annulus as an extremely thin film unmixed with air.

2. A rotary oil burner comprising: rotary drive means; lateral top and bottom dished plates mounted concave toward each other and coaxi-ally in spaced relation on .said drive means and together defining an atomizing chamber; said dished top plate including an annulus extending exteriorly of said chamber outwardly and downwardly a substantial distance beyond the edge of said bottom plate, said annulus defining a wide annular fuel spreading surface; air conduits traversing said chamber and connecting the region below said bottom plate with the region above said top plate; a first fan means mounted on said drive means below said bottom plate for driving air vertically upward through said conduits thereby cooling said atomizing chamber without the introduction of air therein-to; means for feeding fuel to said atomizing chamber, said fuel upon actuation of said rotary drive means being thrown radially outward and focused by the converging dished portions of said plates and reformed outside of said atomizing chamber as a thin film flowing unmixed with air from inner to outer edge portions of said fuel spreading surface; and an annular series of fan blades mounted on and for rotation with said bottom plate, the fan blades of said series being positioned alongside the dished portion of said bottom plate and below said surface for producing at points close to said surface an annular air blast rotating at substantially the same speed as said plates, said fan blades being inclined to direct said air blast upwardly-outwardly against the oil film flowing across said surface, said air blast further thinning by squashing and accelerating said oil film whereby it is discharged at high speed from the peripheral edge of said annulus as an extremely thin film unmixed with air.

3. A rotary oil burner as defined in claim 2, and a dished cover element spaced above said top plate and fixed for rotation therewith, the dished portion of said cover element overhanging said dished annulus whereby the air driven upwardly through said conduits is formed by said cover element into a downwardly directed annular air stream which intersects said thin film when discharged from said peripheral edge.

4. In a rotary oil burner, a shaft, means providing an annular fuel spreading surface fixed for rotation with said shaft, means for delivering fuel unmixed with air to said surface whereby upon said rotation the fuel is flowed radially outward on said surface, means delivering an annular blast of air to said fuel spreading surface for accelerating said radially outward fuel flow, and a wiper mounted on and for rotation relative to said shaft and having end portions engaging over the peripheral edge of said surface, said wiper by inertia scraping said peripheral edge upon changes in the speed of said rotation of said shaft.

5. In a rotary oil burner, a member forming an inclined fuel distributing surface said member having a peripheral edge, means for rotating said member, means for feeding oil to said surface for flowing past said edge upon said rotation, a fan below said member for directing a stream of air along said surface accelerating said flow of oil,

a cover element spaced from said member and having an edge adjacent said peripheral edge, means for delivering air radially outward in the region between said member and said cover element for discharge outside said peripheral edge, and an inertial wiper mounted to rotate freely within said region, said wiper having resilient arms which engage said peripheral edge when said member rotates at low speeds and which swing away from said peripheral edge when said member rot-ates at higher speeds.

References Cited in the file of this patent UNITED STATES PATENTS 1,636,317 Nyrop July 19, 1927 1,641,356 Roach Sept. 6, 1927 2,025,526 Rodler Dec. 24, 1935 2,030,123 Tiffany Feb. 11, 1936 2,088,742 Hayward Aug. 3, 1937 2,568,763 Ray Sept. 25, 1951 2,738,837 McGi-llis et a1 Mar. 20, 1956 FOREIGN PATENTS 818,481 France June 21, 1957 

